// 定义一个变量和一个mixin
$baseFontSize = 75 // 默认基准font-size
px2rem(name, px)
  {name} (px / $baseFontSize) * 1rem
// 背景图片
bg-image($url)
  background-image url($url + '@2x.png')
  @media (-webkit-min-device-pixel-ratio: 3), (min-device-pixel-ratio: 3)
    background-image url($url + '@3x.png')
// 不换行
no-wrap()
  text-overflow ellipsis
  overflow hidden
  white-space nowrap
// 扩展点击区域
extend-click()
  position relative
  &:before
    content ''
    position absolute
    top -0.1rem
    left -0.1rem
    right -0.1rem
    bottom -0.1rem
// boder-1px 1px
// 下边框
border-1px($color)
  position relative
  &:after
    display block
    position absolute
    left 0
    bottom 0
    width 100%
    border-top 1px solid $color
    content ''
